With Project Purity destroyed, his father dead, and his old home shut off from the rest of the Wasteland, the only good memory of his past that William Madison can hang on to is the lullaby his father sang for him, and him alone. When he finds himself in Equestria, he would've taken it in stride, but it changes when he hears that same lullaby - HIS lullaby - in this strange world. Confused, William must find the connection between the lullaby and his life.